Experimental studies of the electron transport systems in the mitochondrial membrane, in component sub-systems and in bacterial model systems utilizing electron paramagnetic resonance as a key tool. Magnetic interactions among membrane components and response to exogenous paramagnetic relaxers will be studied to deduce spatial vectorial organization. Methods used will include changes in spin-lattice relaxation times induced by dipolar magnetic coupling between membrane-bound system clusters and other components. These will be followed by continuous saturation of the spectra and by spin-echo EPR, with construction of such a spectrometer to be one of the key projects in this proposed research. Oriented multilayers will be used to achieve a degree of "crystallinity".